KVM: selftests: Add blessed SVE registers to get-reg-list

Add support for the SVE registers to get-reg-list and create a
new test, get-reg-list-sve, which tests them when running on a
machine with SVE support.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20201029201703.102716-5-drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>